<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="../resct18/react.development.js"></script>
    <script src="../resct18/react-dom.development.js"></script>
    <style>
 .box{
        width: 300px;
        height: 300px;
        background-color: blue;
    }
    </style>
</head>
<body>
    <div id="app"></div>
    <script>
        const VDOM=React.createElement('div',{className:'box'},'hello')
        ReactDOM.createRoot(document.getElementById('app')).render(VDOM)
    </script>
</body>
</html>